As shown in Japanese Patent Laid-Open No. 06/002,984, the conventional adsorptive heat exchange modules in adsorptive freezer, adsorptive air conditioner, etc. adopt such a system that many circular or polygonal metal plates are installed along the outer circumference of each of heat transfer pipes made of aluminum, copper, etc. to constitute fins and tubes and, in the gap of the fins, a solid adsorbent such as zeolite, silica gel or active carbon is filled. In such a constitution however, an area where the solid moisture absorber contacts to the fin is small and, therefore, there are many problems that conductive efficiency of heat is bad, that a filling state of the filled layer of the solid moisture absorber is affected as a result of moisture absorption and desorption and that spaces are generated between the solid moisture absorber and the fin or among the solid moisture absorbers whereby heat transfer efficiency lowers.
In order to solve those problems, there have been proposals such as a method where a solid moisture absorber such as silica gel or zeolite is applied onto a heat exchange surface (Japanese Patent Laid-Open No. 05/322,364); and a method where an adsorbent such as active alumina, active carbon, zeolite or molecular sieve is adhered to a metal fin using a powdery adhesive of a thermo-setting type or a powdery adhesive of a thermoplastic type (Japanese Patent Laid-Open No. 2000/018,767). Further, there have been shown examples such as a method where, in order to enhance the heat exchange efficiency between adsorbent and metal surface, a spherical adsorbent such as zeolite, silica gel or active alumina is installed onto a heat exchange surface via a heat conductive layer part (Japanese Patent Laid-Open No. 08/271,085); an adsorbent where graphite is added, in order to enhance the heat conductivity, to silica gel acting as an adsorbent and an adsorptive heat exchanger using the same (Japanese Patent Laid-Open No. 10/286,460); and an example where graphite and silicon carbide are added to an adhesive resin (Japanese Patent Laid-Open No. 2004/263,959).
As mentioned above, as to moisture absorbers which have been used as conventional heat exchange modules, those of an inorganic type such as silica gel, zeolite, active alumina, active carbon and molecular sieve have been used. Mechanism of adsorption by those adsorptive agents is due to adsorption of water molecules with surfaces of pores of each of inorganic adsorptive agents and there are characteristics that moisture absorptive ability is high and that handling as particles is easy.
However, any of those adsorptive agents is an inorganic substance and, therefore, there is a problem that, it is hard and, when moisture absorption and desorption are repeated for a long period, there occurs a phenomenon in which the adsorptive agent is cracked due to a slight change in volume accompanied by moisture absorption and desorption or is crushed or pulverized resulting in a lowering of property. In addition, all of those inorganic adsorptive agents are strongly bonded to water molecules and, therefore, although the adsorption takes place strongly, big energy is needed for cleaving the bond upon desorption or, in other words, high temperature is needed for regeneration whereby that is not preferred in view of conversation of energy.
Further, in the case of such an inorganic substance, since it is porous and is apt to become a state where moisture is abundant, bacteria or fungi are apt to grow and there are some cases where, due to them, dust causing damage of health or abnormal smell is generated whereby problems happen.